141 research outputs found
A Fresh Approach to Forecasting in Astroparticle Physics and Dark Matter Searches
We present a toolbox of new techniques and concepts for the efficient
forecasting of experimental sensitivities. These are applicable to a large
range of scenarios in (astro-)particle physics, and based on the Fisher
information formalism. Fisher information provides an answer to the question
what is the maximum extractable information from a given observation?. It is a
common tool for the forecasting of experimental sensitivities in many branches
of science, but rarely used in astroparticle physics or searches for particle
dark matter. After briefly reviewing the Fisher information matrix of general
Poisson likelihoods, we propose very compact expressions for estimating
expected exclusion and discovery limits (equivalent counts method). We
demonstrate by comparison with Monte Carlo results that they remain
surprisingly accurate even deep in the Poisson regime. We show how correlated
background systematics can be efficiently accounted for by a treatment based on
Gaussian random fields. Finally, we introduce the novel concept of Fisher
information flux. It can be thought of as a generalization of the commonly used
signal-to-noise ratio, while accounting for the non-local properties and
saturation effects of background and instrumental uncertainties. It is a
powerful and flexible tool ready to be used as core concept for informed
strategy development in astroparticle physics and searches for particle dark
matter.Comment: 33 pages, 12 figure
A Unique Multi-Messenger Signal of QCD Axion Dark Matter
We propose a multi-messenger probe of QCD axion Dark Matter based on
observations of black hole-neutron star binary inspirals. It is suggested that
a dense Dark Matter spike may grow around intermediate mass black holes
(). The presence of such a spike produces
two unique effects: a distinct phase shift in the gravitational wave strain
during the inspiral and an enhancement of the radio emission due to the
resonant axion-photon conversion occurring in the neutron star magnetosphere
throughout the inspiral and merger. Remarkably, the observation of the
gravitational wave signal can be used to infer the Dark Matter density and,
consequently, to predict the radio emission. We study the projected reach of
the LISA interferometer and next-generation radio telescopes such as the Square
Kilometre Array. Given a sufficiently nearby system, such observations will
potentially allow for the detection of QCD axion Dark Matter in the mass range
to .Comment: 5 pages, 3 figures. Appendix added with additional figures. Updated
to published versio
MIRU-VNTRplus: datenbankgestützte polyphasische Analyse von Mycobacterium tuberculosis complex Genotypisierungsdaten
Die molekulare Typisierung von Isolaten des Mycobacterium tuberculosis complex (MTBC) ist für viele epidemiologische Anwendungen von Bedeutung. Das Verfahren der Variable Number Tandem Repeats (VNTR) Typisierung wird hierzu immer wichtiger, da es sehr diskriminierend und sehr reproduzierbar ist. Bis jetzt gibt es noch keine Software zur Analyse von VNTR-Typisierungsdaten, die eine repräsentative und gut charakterisierte Referenzdatenbank beinhaltet. In die hier vorgestellte Datenbank wurden 187 Stämme der wichtigsten Lineages des MTBC aufgenommen. Für jeden dieser Stämme sind neben den Basisdaten auch VNTR-Daten für 24 Loki und vier weitere genetische Marker vorhanden. Benutzer können ihre Isolate auf zwei Arten mit der Referenzdatenbank vergleichen, durch Ähnlichkeitssuche oder durch Auswertung der Gruppierung in einem phylogenetischen Baum. Die für die Ähnlichkeitssuche notwendigen Schwellenwerte wurden durch eine Auswertung der Suchergebnisse für die Referenzstämme bestimmt
Dark Matter Model or Mass, but Not Both: Assessing Near-Future Direct Searches with Benchmark-free Forecasting
Forecasting the signal discrimination power of dark matter (DM) searches is
commonly limited to a set of arbitrary benchmark points. We introduce new
methods for benchmark-free forecasting that instead allow an exhaustive
exploration and visualization of the phenomenological distinctiveness of DM
models, based on standard hypothesis testing. Using this method, we reassess
the signal discrimination power of future liquid Xenon and Argon direct DM
searches. We quantify the parameter regions where various non-relativistic
effective operators, millicharged DM, and magnetic dipole DM can be
discriminated, and where upper limits on the DM mass can be found. We find that
including an Argon target substantially improves the prospects for
reconstructing the DM properties. We also show that only in a small region with
DM masses in the range 20-100 GeV and DM-nucleon cross sections a factor of a
few below current bounds can near-future Xenon and Argon detectors discriminate
both the DM-nucleon interaction and the DM mass simultaneously. In all other
regions only one or the other can be obtained.Comment: 5 pages, 4 figures + appendices. Code for the calculations throughout
the paper can be found at
https://github.com/tedwards2412/benchmark_free_forecasting/ . v2: Minor
corrections, matches version published in PRL as "Assessing Near-Future
Direct Dark Matter Searches with Benchmark-Free Forecasting
Digging for Dark Matter: Spectral Analysis and Discovery Potential of Paleo-Detectors
Paleo-detectors are a recently proposed method for the direct detection of
Dark Matter (DM). In such detectors, one would search for the persistent damage
features left by DM--nucleus interactions in ancient minerals. Initial
sensitivity projections have shown that paleo-detectors could probe much of the
remaining Weakly Interacting Massive Particle (WIMP) parameter space. In this
paper, we improve upon the cut-and-count approach previously used to estimate
the sensitivity by performing a full spectral analysis of the background- and
DM-induced signal spectra. We consider two scenarios for the systematic errors
on the background spectra: i) systematic errors on the normalization only, and
ii) systematic errors on the shape of the backgrounds. We find that the
projected sensitivity is rather robust to imperfect knowledge of the
backgrounds. Finally, we study how well the parameters of the true WIMP model
could be reconstructed in the hypothetical case of a WIMP discovery.Comment: 14 pages, 5 figures, code available at
https://github.com/tedwards2412/paleo_detectors/ . v2: Added additional
analysis theory details, matches version published in PR
Transient Radio Signatures from Neutron Star Encounters with QCD Axion Miniclusters
The QCD axion is expected to form dense structures known as axion
miniclusters if the Peccei-Quinn symmetry is broken after inflation.
Miniclusters that have survived until today will interact with neutron stars
(NSs) in the Milky Way to produce transient radio signals from axion-photon
conversion in the NS magnetosphere. We quantify the properties of these
encounters and find that they occur frequently
(); last between a day and a few months;
are spatially clustered towards the Galactic center; and can reach observable
fluxes. These radio transients are within reach of current generation
telescopes and therefore offer a promising pathway to discovering QCD axion
dark matter.Comment: 11 pages, 5 figures. Code is available online at
https://github.com/bradkav/axion-miniclusters/ (archived at
https://doi.org/10.5281/zenodo.4006128 ). Joint submission with "Stellar
Disruption of Axion Miniclusters in the Milky Way" in astro-ph
(arXiv:2011.05377). Updated to match published versio
Stellar Disruption of Axion Miniclusters in the Milky Way
Axion miniclusters are dense bound structures of dark matter axions that are
predicted to form in the post-inflationary Peccei-Quinn symmetry breaking
scenario. Although dense, miniclusters can easily be perturbed or even become
unbound by interactions with baryonic objects such as stars. Here, we
characterize the spatial distribution and properties of miniclusters in the
Milky Way (MW) today after undergoing these stellar interactions throughout
their lifetime. We do this by performing a suite of Monte Carlo simulations
which track the miniclusters' structure and, in particular, accounts for
partial disruption and mass loss through successive interactions. We consider
two density profiles - Navarro-Frenk-White (NFW) and Power-law (PL) - for the
individual miniclusters in order to bracket the uncertainties on the
minicluster population today due to their uncertain formation history. For our
fiducial analysis at the Solar position, we find a survival probability of 99%
for miniclusters with PL profiles and 46% for those with NFW profiles. Our work
extends previous estimates of this local survival probability to the entire MW.
We find that towards the Galactic center, the survival probabilities drop
drastically. Although we present results for a particular initial halo mass
function, our simulations can be easily recast to different models using the
provided data and code. Finally, we comment on the impact of our results on
lensing, direct, and indirect detection.Comment: 31 pages, 18 figures. Code available online at
https://github.com/bradkav/axion-miniclusters/ (archived at
https://doi.org/10.5281/zenodo.4006128 ). Joint submission w/ "Transient
Radio Signatures from Neutron Star Encounters with QCD Axion Miniclusters",
arXiv:2011.05378 . v2: Minor changes and references added. v3: Updated to
match version published in PR
Continuidad y cambio. Problemas de la neolitización en el este de la Península Ibérica
This paper analyses the transition from a hunter-gatherer economy to another one based on agriculture and animal-husbandry in the eastern part of the Iberian Península. Based on a comparative study of epipaleolithic and early neolithic sites with radiocarbon dates and/ or studies of fauna or cereals finds, we propose three models to explain the archaeological record.Se analiza la transición de una economía de cazadores y recolectores a otra basada en la agricultura y el pastoreo en la zona este de la Península Ibérica. Partiendo de un estudio comparativo de los yacimientos del Epipaleolítico y Neolítico antiguo con dataciones de carbono- 14 y/o estudios de fauna y hallazgos de cereales se proponen tres modelos para explicar el registro arqueológico
Based Upon Repeat Pattern (BURP): an algorithm to characterize the long-term evolution of Staphylococcus aureus populations based on spa polymorphisms
Mellmann A, Weniger T, Berssenbrügge C, et al. Based Upon Repeat Pattern (BURP): an algorithm to characterize the long-term evolution of Staphylococcus aureus populations based on spa polymorphisms. BMC MICROBIOLOGY. 2007;7(1):98.Background: For typing of Staphylococcus aureus, DNA sequencing of the repeat region of the protein A ( spa) gene is a well established discriminatory method for outbreak investigations. Recently, it was hypothesized that this region also reflects long-term epidemiology. However, no automated and objective algorithm existed to cluster different repeat regions. In this study, the Based Upon Repeat Pattern ( BURP) implementation that is a heuristic variant of the newly described EDSI algorithm was investigated to infer the clonal relatedness of different spa types. For calibration of BURP parameters, 400 representative S. aureus strains with different spa types were characterized by MLST and clustered using eBURST as "gold standard" for their phylogeny. Typing concordance analysis between eBURST and BURP clustering ( spa-CC) were performed using all possible BURP parameters to determine their optimal combination. BURP was subsequently evaluated with a strain collection reflecting the breadth of diversity of S. aureus (JCM 2002; 40: 4544). Results: In total, the 400 strains exhibited 122 different MLST types. eBURST grouped them into 23 clonal complexes (CC; 354 isolates) and 33 singletons (46 isolates). BURP clustering of spa types using all possible parameter combinations and subsequent comparison with eBURST CCs resulted in concordances ranging from 8.2 to 96.2%. However, 96.2% concordance was reached only if spa types shorter than 8 repeats were excluded, which resulted in 37% excluded spa types. Therefore, the optimal combination of the BURP parameters was "exclude spa types shorter than 5 repeats" and "cluster spa types into spa-CC if cost distances are less than 4" exhibiting 95.3% concordance to eBURST. This algorithm identified 24 spa-CCs, 40 singletons, and excluded only 7.8% spa types. Analyzing the natural population with these parameters, the comparison of whole-genome micro-array groupings ( at the level of 0.31 Pearson correlation index) and spa-CCs gave a concordance of 87.1%; BURP spa-CCs vs. manually grouped spa types resulted in 95.7% concordance. Conclusion: BURP is the first automated and objective tool to infer clonal relatedness from spa repeat regions. It is able to extract an evolutionary signal rather congruent to MLST and micro-array data
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